powerpc: Add a local_flush_tlb_page to handle kmap_atomic invalidates

The tlb invalidates in kmap_atomic/kunmap_atomic can be called from
IRQ context, however they are only local invalidates (on the processor
that the kmap was called on).  In the future we want to use IPIs to
do tlb invalidates this causes issue since flush_tlb_page() is considered
a broadcast invalidate.

Add local_flush_tlb_page() as a non-broadcast invalidate and use it in
kmap_atomic() since we don't have enough information in the
flush_tlb_page() call to determine its local.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
---
 arch/powerpc/include/asm/highmem.h  |    4 ++--
 arch/powerpc/include/asm/tlbflush.h |   14 ++++++++++++++
 2 files changed, 16 insertions(+), 2 deletions(-)

On Wed, 2008-11-19 at 09:53 -0600, Kumar Gala wrote:
> The tlb invalidates in kmap_atomic/kunmap_atomic can be called from
> IRQ context, however they are only local invalidates (on the processor
> that the kmap was called on).  In the future we want to use IPIs to
> do tlb invalidates this causes issue since flush_tlb_page() is considered
> a broadcast invalidate.
> 
> Add local_flush_tlb_page() as a non-broadcast invalidate and use it in
> kmap_atomic() since we don't have enough information in the
> flush_tlb_page() call to determine its local.
> 
> Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

> ---
>  arch/powerpc/include/asm/highmem.h  |    4 ++--
>  arch/powerpc/include/asm/tlbflush.h |   14 ++++++++++++++
>  2 files changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/highmem.h b/arch/powerpc/include/asm/highmem.h
> index 91c5895..7dc52ec 100644
> --- a/arch/powerpc/include/asm/highmem.h
> +++ b/arch/powerpc/include/asm/highmem.h
> @@ -85,7 +85,7 @@ static inline void *kmap_atomic_prot(struct page *page, enum km_type type, pgpro
>  	BUG_ON(!pte_none(*(kmap_pte-idx)));
>  #endif
>  	__set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot));
> -	flush_tlb_page(NULL, vaddr);
> +	local_flush_tlb_page(vaddr);
>  
>  	return (void*) vaddr;
>  }
> @@ -113,7 +113,7 @@ static inline void kunmap_atomic(void *kvaddr, enum km_type type)
>  	 * this pte without first remap it
>  	 */
>  	pte_clear(&init_mm, vaddr, kmap_pte-idx);
> -	flush_tlb_page(NULL, vaddr);
> +	local_flush_tlb_page(vaddr);
>  #endif
>  	pagefault_enable();
>  }
> diff --git a/arch/powerpc/include/asm/tlbflush.h b/arch/powerpc/include/asm/tlbflush.h
> index a2c6bfd..93716a9 100644
> --- a/arch/powerpc/include/asm/tlbflush.h
> +++ b/arch/powerpc/include/asm/tlbflush.h
> @@ -6,6 +6,7 @@
>   *
>   *  - flush_tlb_mm(mm) flushes the specified mm context TLB's
>   *  - flush_tlb_page(vma, vmaddr) flushes one page
> + *  - local_flush_tlb_page(vmaddr) flushes one page on the local processor
>   *  - flush_tlb_page_nohash(vma, vmaddr) flushes one page if SW loaded TLB
>   *  - flush_tlb_range(vma, start, end) flushes a range of pages
>   *  - flush_tlb_kernel_range(start, end) flushes a range of kernel pages
> @@ -44,6 +45,11 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
>  	_tlbil_pid(mm->context.id);
>  }
>  
> +static inline void local_flush_tlb_page(unsigned long vmaddr)
> +{
> +	_tlbil_va(vmaddr, 0);
> +}
> +
>  static inline void flush_tlb_page(struct vm_area_struct *vma,
>  				  unsigned long vmaddr)
>  {
> @@ -81,6 +87,10 @@ extern void flush_tlb_page_nohash(struct vm_area_struct *vma, unsigned long addr
>  extern void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
>  			    unsigned long end);
>  extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);
> +static inline void local_flush_tlb_page(unsigned long vmaddr)
> +{
> +	flush_tlb_page(NULL, vmaddr);
> +}
>  
>  #else
>  /*
> @@ -138,6 +148,10 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
>  {
>  }
>  
> +static inline void local_flush_tlb_page(unsigned long vmaddr)
> +{
> +}
> +
>  static inline void flush_tlb_page(struct vm_area_struct *vma,
>  				  unsigned long vmaddr)
>  {